Plastic shotshell with sealing rings

ABSTRACT

A plastic shotshell case to be loaded with powder and shot charges and wads separating the shot and powder; the plastic case having peripheral ribs or rings at the exterior adjacent the open mouth of the case and effectively sealing the case wall against the shotshell chamber in the barrel of the shotgun; the exterior peripheral surface of the case wall being smooth at a location forwardly of the sealing ribs.

United States Patent Herter Mar. 27, 1973 1 1 PLASTIC SHOTSHELL WITHSEALING 3,284,560 11/1966 King et al. ..1o2/43 P RIN GS FOREIGN PATENTSOR APPLICATIONS [75] Inventor: George L. Herter, Waseca, Minn.

6,500,147 1965 Netherlands ..102/43 P W M' [73] Ass1gnee Herter 5 Incaseca 1nn Pfima'y Examiner Robert F. Stab] led: Dec. 21, 1970Attorney-Williamson, Palmatier & Bains, H. Dale [211 App} NOJ 100,043Palmatrer, Herman H. Bams and Malcolm L. Moore ABS'I RACT S "102/43 102/A plastic shotshell case to be loaded with powder and I o a A 6 I I 6 6I 6 I n v 6 6 6 I 1 I 6 I I I I 6 I n u u 6 6 l0 Fleld of Search R, P,42, 38, p the plastic case having peripheral or i g at the exterioradjacent the open mouth of the case [56] References C'ted andeffectively sealing the case wall against the UNITED STATES PATENTSshotshell chamber in the barrel of the shotgun; the extenor penpheralsurface of the case wall being smooth 3,363,562 1/1968 Stadler et al...102/43 P at a location forwardly of the sealing ribs. 3,517,617 6/1970Hall ..102/43 P I 3,103,170 9/1963 Covington, Jr. et a1. ..102 43 P 8Chums, D g Figures 3,613,191 10/1971 Minnich etal ..102/43RPATENTEDHARZTIQ'IS INVENTQR.

PLASTIC SI'IOTSI-IELL WITH SEALING RINGS BRIEF SUMMARY OF THE INVENTIONThe plastic shotshell case with a plurality of outwardly projectingrings or ribs extending peripherally of the case adjacent the open mouthor closure end of the case that function principally at the instant offiring, at which time the rapidly burning powder gases are expanding andcreating extremely high gas pressures within the shotshell case and theshotgun barrel. At this instant, the gas pressure forces the case walloutwardly and causes the rings to engage and seal against the barrelwall to prevent gas from escaping in a rearward direction along theexterior surface of the case and adjacent the breech bolt of theshotgun.

The plastic shotshell case is formed by injection molding of plastic;and may be formed principally of polyethylene plastic; or it may bedesired to form the shotshell case principally of a polycarbonateplastic.

The exterior peripheral surface of the shotshell case wall is striatedin a longitudinal direction throughout a major portion of the length ofthe shotshell case wall; and I at locations forwardly of the rings, thepolyethylene case wall has its exterior peripheral surface smooth andunbroken for a distance of approximately half the diameter of thetubular shotshell case for forming the star crimp closure of a shotgunshell after the shell is loaded with the shot, powder and wads. Thesmooth exterior peripheral surface at this portion of the shotshellprevents or minimizes through numerous loadings and reloadings of theshotshell case, splitting of the case due to repeated folding in thenumerous reloads and formations of the star crimp for enclosing theinterior of the shotshell case.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged elevation viewof the plastic shotshell case.

FIG. 2 is a greatly enlarged detail section view taken approximately at2-2 in FIG. 1 and showing the relative size relationship between theribs or rings and the case wall and the relationship between the severalribs along the case wall.

FIG. 3 is an elevation view at a reduced scale of the shotshell which ispartly broken away for clarity of detail and shown applied into theshotshell chamber of the barrel of a shotgun and retained by the breechbolt, the details of the breech construction of the shotgun barrel aremostly eliminated.

FIG. 4 is an elevation view of a modified form of plastic shotshell casewherein the closure is formed by a top wad.

DETAILED DESCRIPTION OF THE INVENTION The plastic shotshell case isindicated in general by numeral 10 and is formed by injection molding.The shotshell case is integrally formed in one piece, and the entireshotshell case is formed in one molding process so that the entire caseis integral and all portions of it are of the same material. Theshotshell case may be formed of polyethylene plastic, and may have smallquantities of other types of plastics mixed in with the polyethylene toobtain certain strength and other characteristics. Likewise, it may bedesirable to form the all plastic shotshell case 10 of a polycarbonateplastic, either a pure polycarbonate or possibly with other plasticsmixed in to give the plastic certain characteristics. It will beunderstood that polycarbonate plastic is very hard and withstands highimpact, 5 and has been successfully used in the production of suchshotshell cases, which are subsequently made into shotgun shells forhunting and other types of shooting.

The shotshell case has a base portion 11 and an ejecting flange 12, andan elongate tubular case wall 13 terminating at its front end 14 in anopen mouth through which the ejectable components of the shotshell,including the shot charge, powder charge, the wads, etc., are loadedinto the shotshell case for forming the shotshell. Of course, the caseis closed at the base 11 and a primer is mounted in the base forignition of the powder charge upon firing the shotshell in a shotgun.Along a major portion of the case wall 13, the exterior peripheralsurface of the case wall is striated as indicated at 15. The striatetexture of the exterior peripheral surface contributes to ease andcomfort of handling the shotshell case and the shotshells which areeventually made therefrom, and to give the shotshell case a pleasingappearance.

The forward portion 16 of the tubular case wall 13 is smooth at itsexterior peripheral surface for a distance along the length of the casefrom the open mouth equaling approximately half the diameter tofacilitate the formation of a star crimp in the smooth surfaced frontend portion 16. It will be understood that in the formation of a starcrimp the front portion 16 of the case wall is folded numerous times inan accordian pleat type shape around the periphery of the case wall sothat upon forming the star crimp and upon the repeated formations ofstar crimps and the opening of the crimps under force of the shot andgas pressures in the shotshell case, there is some tendency for the casewall to split because of the folding. However, the smooth exteriorperipheral surface of the portion 16 of the case wall adjacent the openmouth where the star crimp is formed tends to minimize the likelihood ofthere being any splitting of the shotshell case in spite of numerousreloadings of the polyethylene shotshell case. It has been found that ashotshell case such as that disclosed herein may be reloaded eight toten times without splitting the shotshell case in the vicinity of thefront end portion 16 even though the star crimps are formed a likenumber of times.

At the exterior peripheral surface of the case wall 13, the portions 15and 16 are separated by a plurality of outwardly projecting cylindricalrings or ribs 17 on the exterior periphery of the case wall. The ribs orrings 17 project only a very small distance from the peripheral face ofthe case wall, so that these ribs 17 will not interfere with the normalhandling and usage of the shotshell case during loading of the case andduring insertion of the loaded shotshell into the barrel 20 of a shotgunor the removal of the expended or emptied case from the barrel. The ribs17 have a thickness or height in a radial direction only approximatelyonetenth the thickness of the case wall. The width of each of the ribs17, in a direction longitudinally of the case wall, is of the same orderas the thickness of the case wall in the vicinity of these ribs. Thespacing between the ribs 17 is of the same order of dimensions as thewidth of these ribs. It is preferable that the forwardmost rib 17 isdisposed a sufficient distance from the open mouth end 14 of theshotshell case so that the entire star crimp can be formed in the endportion 16 of the case wall without distorting the forwardmost rib 17.

When the shotshell case is properly loaded with powder, wads, shot, andthe case is closed for firing, the loaded shotshell 19 may be insertedinto the shotshell chamber of the shotgun barrel and be retained thereinby the breech bolt 21 in a well known manner. The firing of theshotshell causes instant ignition of the powder in the shotshell caseand development of high gas pressures due to the combustion andexpansion of the powder gases as the shot charge is suddenly set intomotion along the gun barrel and toward the muzzle end. As the gaspressures in the shotshell case build up, the shotshell case wall 13expands very slightly against the interior surface of the shotshellchamber of the barrel and the ribs 17 produce a highly efficient sealbetween the shotshell case 13 and the barrel 20 so as to prevent powdergases, or other materials such as unburned powder, from escaping in adirection rearwardly along the case wall 13. and toward the breech bolt21. The seal produced by the ribs 17 bearing against the barreleffectively prevents the loss of gas pressure in a reverse directionand, as a result, all of the gas is effectively utilized foracceleration and propulsion of the shot charge toward the muzzle of thebarrel.

In the form of shotshell 25 illustrated in FIG. 4, the shotshell case 26has a plurality of sealing ribs 17' identical to those illustrated inFIGS. 1 3. In this form of the shotshell case 26, the case wall 13'terminates just forwardly of the forwardmost rib 17, as indicated at14', and this forward edge of the shotshell case wall 13 is simplyrolled over slightly to retain the end wad or closure wad 27 appliedwithin the periphery of the case wall and over the shot confined in theshotshell 25.

As previously described in connection with FIGS. 1 3, the ribs 17 serveto seal the case wall 13' against the shotgun barrel to prevent highpressure gases from traveling or leaking rearwardly along the shotshellcase upon ignition.

It will be seen that I have provided a new and improved all plasticshotshell case with sealing ribs extending peripherally adjacent themouth end of the case wall to seal against the shotshell chamber of theshotgun barrel upon firing of the shotshell when high pressures aredeveloped through expansion of powder gases. The plastic shotshell casealso has a smooth and unbroken exterior peripheral surface in theforward portion of the case wall which is utilized for the star crimp soas to contribute to the continued life of the shotshell case throughnumerous reloadings without splitting at the forward star crimp portionof the shotshell case.

What is claimed is:

l. A shotshell case comprising,

a tubular case wall constructed of plastic, the case wall having a frontclosure end from which the shot charge exits upon ignition of the powdercharge,

and a plurality of external circumferential ribs on the case wall andformed integrally thereof adjacent the closure end, said ribs having athickness in a radial direction several times less than the thickness ofthe case wall, said ribs being en ageable with the barrel wall to sealagainst the arrel and prevent gases under pressure from escaping alongthe case wall and toward the breech bolt of the shotgun only upon firingthe shotshell and ignition of the powder therein.

2. The shotshell case according to claim 1 and said ribs having a widthin a direction along the case wall on the same order as the thicknessofthe case wall.

3. The shotshell case according to claim 2 and said ribs being spacedfrom each other by a distance of the same order as the width of theshells.

4. The shotshell case according to claim 1 and said case wall beingconstructed of plastic consisting to a large degree of polycarbonate.

5. The shotshell case according to claim 1 and said case wall beingconstructed of plastic consisting to a large degree of polyethylene.

6. The shotshell case according to claim 1 and the case wall extendingtoward the front well beyond the circumferential ribs and sufficientlyto produce a closure by a star crimp.

7. The shotshell case according to claim 1 and the case wall terminatingimmediately forwardly of the ribs to receive and retain an end wad toeffect the closure.

8. The shotshell case according to claim 6 and the ex terior surface ofthe case wall at locations forwardly of and rearwardly of the ribs beingrespectively smooth and striated in a longitudinal direction.

1. A shotshell case comprising, a tubular case wall constructed ofplastic, the case wall having a front closure end from which the shotcharge exits upon ignition of the powder charge, and a plurality ofexternal circumferential ribs on the case wall and formed integrallythereof adjacent the closure end, said ribs having a thickness in aradial direction several times less than the thickness of the case wall,said ribs being engageable with the barrel wall to seal against thebarrel and prevent gases under pressure from escaping along the casewall and toward the breech bolt of the shotgun only upon firing theshotshell and ignition of the powder therein.
 2. The shotshell caseaccording to claim 1 and said ribs having a width in a direction alongthe case wall on the same order as the thickness of the case wall. 3.The shotshell case according to claim 2 and said ribs being spaced fromeach other by a distance of the same order as the width of the shells.4. The shotshell case according to claim 1 and said case wall beingconstructed of plastic consisting to a large degree of polycarbonate. 5.The shotshell case according to claim 1 and said case wall beingconstructed of plastic consisting to a large degree of polyethylene. 6.The shotshell case according to claim 1 and the case wall extendingtoward the front well beyond the circumferential ribs and sufficientlyto produce a closure by a star crimp.
 7. The shotshell case according toclaim 1 and the case wall terminating immediately forwardly of the ribsto receive and retain an end wad to effect the closure.
 8. The shotshellcase according to claim 6 and the exterior surface of the case wall atlocations forwardly of and rearwardly of the ribs being respectivelysmooth and striated in a longitudinal direction.